Hi Tommaso, I see your point. You would like that the axis labels change according to the function, isn't it ? This not how this feature is working. In fact is works exactly the same as the Logy and Logx options: When you "set on" one of these options, the axis tick marks are positioned according to a log scale but the axis labels keep their "linear values". So when you use a function to create an axis, the tick marks will be positioned according to this function but the axis labels will keep their "linear values". Therefore adding or subtracting a constant has no visible effect, because it just performs a translation of a linear scale so it remains linear. I have attached a little macro creating a few axis showing this. Cheers, Olivier On Wed, 10 Mar 2004, Tommaso Chiarusi wrote: > Ok, the algorithm is simply > fu = 90 -x[0]; > > But the substance of the problem does not change: with this function > the range is not modified as I wanted... > > > ok... > On Wed, 10 Mar 2004, Olivier Couet wrote: > > > > > > > > > Hi Tommaso, > > > > are you sure that the real algorithm is: > > > > if(x[0]<=90) fu = 90 - x[0]; > > else fu = 90-x[0]; > > > > ?? > > > > because seems to me these two lines are the same as: > > > > fu = 90-x[0]; > > > > Cheers, Olivier > > > > > > On Wed, 10 Mar 2004, Tommaso Chiarusi wrote: > > > > > Hi Olivier, > > > you were right, I made a mistake, in fact the real algorithm is > > > > > > if(x[0]<=90) fu = 90 - x[0]; > > > else fu = 90-x[0]; > > > > > > and not > > > else fu = x[0]-270; > > > > > > Well yesterday I fused...:) > > > > > > > > > buy the way the devicing fact is that, neither with the > > > correct algorithm, the labels on to the plot are not modified > > > accordingly!!! > > > In fact I get simply > > > 180 160 140 120 100 80 60 40 20 0 > > > > > > Moreover, if in the function you set: > > > fu = x[0]*2; > > > > > > just for trying, you get no effect on the range. > > > > > > may be I didn't well understand how TGaxis works with a function. > > > > > > any suggestion? > > > Thank you. > > > Tommaso > > > > > > On Wed, 10 Mar 2004, Olivier Couet wrote: > > > > > > > > > > > Hi Tommaso, > > > > > > > > I looked closer at your examples. I agree with you that the first one > > > > transform the following labels: > > > > > > > > -80 -60 -40 -20 0 20 40 60 80 > > > > > > > > into: > > > > > > > > 80 60 40 20 0 -20 -40 -60 -80 > > > > > > > > But, seems to me the 2nd example transform: > > > > > > > > 0 20 40 60 80 100 120 140 160 180 > > > > > > > > into: > > > > > > > > 90 70 50 30 10 -170 -150 -130 -110 -90 > > > > > > > > Which, I guess, is not what you want. I think you did a mistake in your > > > > 2nd example. > > > > > > > > Cheers, Olivier > > > > > > > > > > > > On Tue, 9 Mar 2004, Tommaso Chiarusi wrote: > > > > > > > > > > > > > > Hello everybody: > > > > > > > > > > OS Linux RH 9 > > > > > ROOT 3.10/02 16 December 2003 > > > > > > > > > > well, I need to reset the labels onto an histogram. > > > > > It has the x axis which ranges from 0 to +180 > > > > > I like it to span from +90 to -90 (yes from positive to negative > > > > > like 90 80 70..10 0 -10 ... -80 -90). > > > > > > > > > > So decided to > > > > > TGaxis method together with a function > > > > > > > > > > > > > > > So I've written the function: > > > > > > > > > > double funz(double *x,double *par) > > > > > { > > > > > double fu=0; > > > > > fu = -x[0]; > > > > > return fu; > > > > > } > > > > > > > > > > and in the body of the macro, > > > > > > > > > > TF1 *f = new TF1("f",funz,-90,90,0); > > > > > TGaxis *tga = new TGaxis(0,0,180,0,"f",510); > > > > > tga->Draw(); > > > > > > > > > > and it works! > > > > > > > > > > note that the spanning of the new scale is independent from the original > > > > > range. > > > > > ----- > > > > > THE QUESTION: > > > > > > > > > > Why the following doesn't give the same result? > > > > > > > > > > I redefine the function, > > > > > > > > > > double funz(double *x,double *par) > > > > > { > > > > > double fu=0; > > > > > if(x[0]<=90) fu = 90 -x[0]; > > > > > if(x[0]>90) fu = x[0]-270; > > > > > > > > > > return fu; > > > > > } > > > > > > > > > > and in the body of the macro, > > > > > > > > > > TF1 *f = new TF1("f",funz,0,180,0); > > > > > TGaxis *tga = new TGaxis(0,0,180,0,"f",510); > > > > > tga->Draw(); > > > > > > > > > > note the different range for f > > > > > > > > > > Best regards, Tommaso > > > > > > > > > > P.S. > > > > > is this mailing list hard-contamined by spam? > > > > > is it true that it will be removed by the CERN mailing list? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- Org: CERN - European Laboratory for Particle Physics. Mail: 1211 Geneve 23 - Switzerland Mailbox: J25910 E-Mail: Olivier.Couet@cern.ch Phone: +41 22 7676522 WWW: http://cern.ch/Olivier.Couet/ Fax: +41 22 7677155
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